public class ConstantDemo {
    public static void main(String[] args){
        //整数数据类型
        //byte1字节
        //short2字节
        System.out.println(300000000); //默认int4字节
        System.out.println(3000L); //long 类型8字节

        //小数
        //float 类型4字节
        System.out.println("float="+10000.1235f);
        System.out.println("float="+1220.25551234F);//4
        //默认 double 类型8字节
        System.out.println("double="+1000.12345678901234567); //13


        //char 字符型2字节
        System.out.println('a');


        //boolean 类型1位
        System.out.println(true);
        System.out.println(false);


    }

}
